class A{
}class B extends A implements D{
}class C extends A{
}interface D{
}class E{
}
public class Test{
public static void main(){
A a = new A();
B b = new B();
E e = new E();
C c = new C();
C d = null;
a = b;
d=b;
d=(D)a;
}
}
}class B extends A implements D{
}class C extends A{
}interface D{
}class E{
}
public class Test{
public static void main(){
A a = new A();
B b = new B();
E e = new E();
C c = new C();
C d = null;
a = b;
d=b;
d=(D)a;
}
}
main里面参数
} class B extends A implements D{
} class C extends A{
} interface D{
} public class Test{
public static void main(){
A a = new A();
B b = new B();
E e = new E();
C c = new C(); D d = null; a = b;
d=b;
d=(D)a; }
}对不起我发错了,应该是这个
System.out.println(b.getClass().getName());
看看输出就知道为什么了